PRODUCT DESCRIPTION Cherne Single-Size Test-Ball® Plugs are expandable rubber test plugs designed to test drain, vent and waste systems in every type of pipe. Utilizing a standard tire air fitting for easy connections, its inflatable design can be inserted through a test tee to seal out-of-round pipe and hard-to-access openings. These plumbing test plugs are available in a variety of nominal sizes to accommodate your DWV testing needs. Cherne Industries is a global leader in pipe plug, blocking and testing. FROM THE MANUFACTURER Cherne's Single-Size Test-Ball Plugs. Made of natural rubber for excellent expansion and memory. Seals both round and out-of-round pipe. Zinc-plated steel chain and ring handle acts as an anchor to prevent plug from sliding down a line. Fits easily through test tees, sanitary tees, floor drains, and other "tight" situations. Broader expansion range than mechanical plugs.